Home made VFD questions/help

I have a mini-lathe with an induction motor 0.8HP, it has a bulge on top housing a capacitor. Starting cap? Running cap?

I like to home-build a VFD as simple as possible. This is just an hobby, nothing fancy but the approach must be sound. I have skills in switching regulators, PFC etc. but not a good grasp on the motor technology and behavior when driven by a synthesized waveform.

I like to receive, from the experts on this NG, comments and suggestions on the validity of my basic design which is as described:

------------------------------ Bridge Rectify 120V to ~160V Peak rectifier with sufficiently large cap.

5000uF @ 250V

Invert by means of an "H" bridge with max duty cycle of 67% to produce the same VxSec as a 120V sine. Average Voltage (VxSec/0.5T) is what determines peak flux. I believe this is what the Motor "wants".

From this point either increase frequency to 90-120Hz at max duty cycle of

63% or reduce linearly frequency and Duty Cycle down to perhaps 2Hz and 2.2% Duty Cycle.

The pulse duration is constant at about 5.6mS in the 2-to-60 Hz region giving a constant V/Hz and will fall to 2.8mS at 120Hz maintaining a 67% duty cycle giving fixed V.

My questions: Is the basic plan safe for the Motor? Is a rectangular wave OK, bipolar pulses at constant amplitude variable Duty cycle? Have I left out something? What?

All figures are back of the envelope, at this point I am looking for a proof of concept.

Thank you for your help.

Mauro Gaetano